Engine flame out on take off.
02-23-2015, 08:24 AM
#1
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Engine flame out on take off.
Flame out on takeoff:
I have a Jet Central Cheetah mounted in a Comp ARF Euro sport. I have twin tanks feeding the engine through a header tank. At my last flying session the engine flamed out on the takeoff roll. I attempted two take offs and in both cases the results were the same.
During the startup sequence, the engine would start up and stabilize at idle rpm fine. I would then run the engine up to full power, I would do it twice, once slowly and then a slam execration. Both time while the plane/engine was stationary the engine worked fine. I would taxi it out, line up and advance the throttle to full power. The power would come up, the model would begin to accelerate and then I would hear a high wine as the engine shut down with white smoke coming out the back. There was no fire, just smoke. I cooled the engine down and recycled the power system for each attempt.
What was different about this situation from the rest of the time I had flown, was I had emptied the fuel tanks except the header tank. I wanted to get a better feel for how much fuel I was using for each flight. I emptied the tanks and filled them up and timed the procedure. So the next time I filled them and timed the fill, I could see how much fuel I put back. That is the only thing that is different as far as I can tell.
When the airplane is stationary the engine works fine, as it accelerates the engines shut down. Is this problem because I emptied the tanks and I have some sort of air trap which shifts position or really the fuel does and inhibits the flow and shuts the engine down. Have the clunks in the take been jammed forward and loose the pick up as the plane accelerates, I don’t know. Any suggestion would help. I will check the clunks in the tank first.
I have a Jet Central Cheetah mounted in a Comp ARF Euro sport. I have twin tanks feeding the engine through a header tank. At my last flying session the engine flamed out on the takeoff roll. I attempted two take offs and in both cases the results were the same.
During the startup sequence, the engine would start up and stabilize at idle rpm fine. I would then run the engine up to full power, I would do it twice, once slowly and then a slam execration. Both time while the plane/engine was stationary the engine worked fine. I would taxi it out, line up and advance the throttle to full power. The power would come up, the model would begin to accelerate and then I would hear a high wine as the engine shut down with white smoke coming out the back. There was no fire, just smoke. I cooled the engine down and recycled the power system for each attempt.
What was different about this situation from the rest of the time I had flown, was I had emptied the fuel tanks except the header tank. I wanted to get a better feel for how much fuel I was using for each flight. I emptied the tanks and filled them up and timed the procedure. So the next time I filled them and timed the fill, I could see how much fuel I put back. That is the only thing that is different as far as I can tell.
When the airplane is stationary the engine works fine, as it accelerates the engines shut down. Is this problem because I emptied the tanks and I have some sort of air trap which shifts position or really the fuel does and inhibits the flow and shuts the engine down. Have the clunks in the take been jammed forward and loose the pick up as the plane accelerates, I don’t know. Any suggestion would help. I will check the clunks in the tank first.
02-23-2015, 11:07 AM
#2
Ok, you have landed in the JetCat forum, but no matter. White smoke is generally a positive indicator that the flameout was caused by air in the lines. The usual causes of a takeoff flameout are an air leak at the UAT or the feed to the UAT which caused it to drain out, trapped air in the inline filter that found it's way to the engine, or some other air leak.
Check the lines for air bubbles. Often enough, the fill line to the UAT doesn't get completely plugged and it sucks air. Festos in the feed lines to the UAT or even after the UAT will sometimes suck air. I have seen trapped air in the filters take several flights before it clears if the system wasn't purged right. Stationary airplane doesn't vibrate. But it does when it bounces around on the gear during taxi and takeoff which will cause trapped air to purge.
You'll just have to find where. Did you look to see what the ECU reported for the shutdown??
Just a side note, my Rafale flamed out in flight the other day with the usual white smoke. After ripping out all the tanks, I found a stopper on the main feed tank had loosened up enough to suck air. Unfortunately, that tank was buried where I had to take everything out of the front of the airplane to get it out.
Check the lines for air bubbles. Often enough, the fill line to the UAT doesn't get completely plugged and it sucks air. Festos in the feed lines to the UAT or even after the UAT will sometimes suck air. I have seen trapped air in the filters take several flights before it clears if the system wasn't purged right. Stationary airplane doesn't vibrate. But it does when it bounces around on the gear during taxi and takeoff which will cause trapped air to purge.
You'll just have to find where. Did you look to see what the ECU reported for the shutdown??
Just a side note, my Rafale flamed out in flight the other day with the usual white smoke. After ripping out all the tanks, I found a stopper on the main feed tank had loosened up enough to suck air. Unfortunately, that tank was buried where I had to take everything out of the front of the airplane to get it out.
Last edited by Thud_Driver; 02-23-2015 at 11:11 AM.
